RESULTS: The constructed integration system comprises of a lactococcal promoter (PnisA or P170), phage attachment site (attP) from bacteriophage TP901-1, a signal peptide (USP45 or SPK1) for translocation of the target protein, and a PrtP344 anchor domain in the case of the integrative vectors for surface display. There were eight successfully constructed integrative vectors with each having a different combination of promoter and signal peptide; pS1, pS2, pS3 and pS4 for secretion, and pSD1, pSD2, pSD3 and pSD4 for surface display of desired protein. The integration of the vectors into the host genome was assisted by a helper vector harbouring the integrase gene. A nuclease gene was used as a reporter and was successfully integrated into the L. lactis genome and Nuc was secreted or displayed as expected. The signal peptide SPK1 was observed to be superior to USP45-LEISSTCDA fusion in the secretion of Nuc. As for the surface display integrative vector, all systems developed were comparable with the exception of the combination of P170 promoter with USP45 signal peptide which gave very low signals in whole cell ELISA.
CONCLUSION: The engineered synthetic integrative vectors have the potential to be used for secretion or surface display of heterologous protein production in lactococcal expression system for research or industrial purposes, especially in live vaccine delivery.
RESULTS: In this study, L-cells were isolated from a primary intestinal cell line to create suitable target cells for insulin expression studies. The isolated cells displayed L-cell properties and were therefore used as an L-cell surrogate. Next, the isolated L-cells were transfected with the recombinant plasmid consisting of an insulin gene located downstream of the GLP-1 promoter. The secretion tests revealed that an increase in glucose concentration from 5 mM to 25 mM induced insulin gene expression in the L-cells by 2.7-fold. Furthermore, L-cells quickly responded to the glucose stimulation; the amount of insulin protein increased 2-fold in the first 30 minutes and then reached a plateau after 90 minutes.
CONCLUSION: Our data showed that L-cells efficiently produced the mature insulin protein. In addition, the insulin protein secretion was positively regulated with glucose induction. In conclusion, GLP-1 promoter and L-cell could be potential candidates for diabetes gene therapy agents.
OBJECTIVE: The main objective of the present review is to highlight the structural signature, classification, its mechanism and application from basic science to medicine and future challenges for this genome editing tool kit.
RESULTS: The present review provides a brief description of the recent development of CRISPR-Cas9 genome editing technology. We discuss the paradigms shift for this next generation genome editing technology, CRISPR. The CRISPR structural significance, classification and its different applications are also being discussed. We portray the future challenges for this extraordinary genome in vivo editing tool. We also highlight the role of CRISPR genome editing in curing many diseases.
CONCLUSION: Scientists and researchers are constantly looking one genome editing tool that is competent, simple and low-cost assembly of nucleases. It can target any particular site without any off-target mutations in the genome. The CRISPR-Cas9 has all of the above characteristics. The genome engineering technology may be a strong and inspiring technology meant for the next generation of drug development.